St. Thomas weather in August

In August, St. Thomas sees average daytime highs of 25°C and overnight lows near 18°C, with 82 mm of rain across 10.2 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 7th-wettest month of the year here.

Day-to-day highs hold fairly steady near 25°C through the month. The sky is clear or mostly clear about 36% of the time in August, and the air most often feels comfortable.

Daylight stretches from about 14 h 24 min at the start of August to 13 h 06 min by month's end. Set against the rest of the year, August is St. Thomas's 3rd-clearest and 12th-windiest month. For the whole year in context, see St. Thomas's year-round climate.

Daytime high
25°
2nd warmest
Overnight low
18°
11th coldest
Rainfall
82 mm
10.2 wet days
Daylight
13 h 48 min
5:36 AM – 7:22 PM
Cloud cover
53%
3rd clearest
Wind
13 km/h
12th windiest
Solar energy
5.64 kWh/m²
Travel score
7.0
out of 10

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 25°C through the month.

A typical August day in St. Thomas reaches about 25°C in the afternoon and slips back to 18°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 21°C and 28°C. Set against its neighbours, August runs about 1°C cooler than July and about 4°C warmer than September.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12519
22519
32519
42519
52519
62518
72518
82518
92518
102518
112518
122518
132518
142518
152518
162518
172518
182418
192418
202418
212418
222418
232418
242418
252418
262417
272417
282417
292417
302417
312417

How August really feels in St. Thomas

Once humidity and wind are folded in, August averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

St. Thomas weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-1° / -7°7511.58.39.20.0
Feb-1° / -7°589.4710.30.0
Mar / -3°7310.34.911.60.1
Apr10° / 9511.71.713.12.1
May17° / 10°9412.1014.45.1
Jun23° / 16°9911.7015.16.6
Jul25° / 19°9612014.86.6
Aug25° / 18°8210.2013.77.0
Sep21° / 14°849.4012.36.6
Oct14° / 8611.50.110.84.0
Nov / 8110.82.69.61.0
Dec / -3°7411.57.18.90.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 36% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 23% of August, with mostly cloudy or overcast conditions the remaining 41%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16040
26040
36040
45941
56040
66040
76040
86040
95941
105941
115941
125941
135941
145941
156040
166040
175941
185941
195842
205842
215941
225842
235842
245842
255842
265842
275842
285842
295842
305842
315842

Chance of precipitation in August

Any precipitation

St. Thomas gets around 82 mm of rain over 10.2 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 33% and peaks near 37% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
336
436
536
635
735
835
935
1035
1135
1235
1335
1435
1535
1635
1734
1834
1933
2033
2133
2232
2332
2431
2530
2630
2730
2829
2929
3030
3130

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

Most of August feels comfortable — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, August lands in the comfortable band about 27% of days. Sticky, muggy-or-worse air turns up on roughly 30% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
11325272681
21425262581
31426272581
41426262581
51427262581
61427262481
71527262480
81527262480
91627262380
101627262370
111627262370
121727262370
131727272270
141727272270
151727272270
161727272260
171727282360
181726282360
191726282360
201726272360
211726272460
221726272460
231826272460
241826262450
251927262450
261927252450
272027252350
282127242350
292227242350
302327232250
312427232250

Wind in August

Winds average 13 km/h in August, the calmest month.

Across August, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze
3114light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 24 min at the start of August to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over August. Sunrise moves from 5:20 AM to 5:53 AM, and sunset from 7:42 PM to 6:57 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.45:207:42
214.35:217:41
314.35:227:39
414.35:237:38
514.25:247:37
614.25:257:36
714.15:267:34
814.15:277:33
914.15:287:32
1014.05:297:30
1114.05:317:29
1213.95:327:27
1313.95:337:26
1413.85:347:25
1513.85:357:23
1613.85:367:22
1713.75:377:20
1813.75:387:19
1913.65:397:17
2013.65:407:15
2113.55:427:14
2213.55:437:12
2313.45:447:10
2413.45:457:09
2513.45:467:07
2613.35:477:05
2713.35:487:04
2813.25:497:02
2913.25:507:00
3013.15:526:59
3113.15:536:57

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.64 kWh/m².

For context, solar energy here swings from a low near 1.34 kWh/m² to a high of 6.64 kWh/m² in June across the year — August's 5.64 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.0Intense
46.0Intense
56.0Bright
66.0Bright
75.9Bright
85.9Bright
95.9Bright
105.8Bright
115.8Bright
125.8Bright
135.7Bright
145.7Bright
155.7Bright
165.6Bright
175.6Bright
185.6Bright
195.5Bright
205.5Bright
215.5Bright
225.4Bright
235.4Bright
245.4Bright
255.3Bright
265.3Bright
275.3Bright
285.2Bright
295.2Bright
305.1Bright
315.1Bright
Planning a trip in August

Is August a good time to visit St. Thomas?

Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.0
Sightseeing
1st-best month of the year
6.1
Beach & pool
2nd-best month of the year

August is one of the better times to visit St. Thomas for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for St. Thomas in August

From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In August, St. Thomas sees daytime highs around 25°C and nights near 18°C. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

Sea temperature near St. Thomas in August

The nearest coast averages about 23°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 17 km away) is warmest in August at about 23°C and coldest in February near 1°C.

It's comfortable for a long swim from Jul 5 to Sep 20 — about 2.6 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan2Bracing
Feb1Bracing
Mar1Bracing
Apr4Bracing
May10Bracing
Jun17Cool
Jul22Refreshing
Aug23Refreshing
Sep21Refreshing
Oct16Cool
Nov10Bracing
Dec5Bracing

UV index in St. Thomas in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in St. Thomas peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 9Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7High
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is St. Thomas?

St. Thomas sits at 42.8°N, 81.2°W, 232 m above sea level, in Canada. The nearest listed city is London, 24 km away.

Topography around St. Thomas

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of St. Thomas.

Within 3 km, the terrain around St. Thomas has only modest variations in elevation — a maximum elevation change of 65 m around an average of 233 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 125 m; within 80 km, significant variations in elevation — a maximum elevation change of 251 m.

The land around St. Thomas is covered by trees (35%) and artificial surfaces (33%) within 3 km, cropland (60%) and trees (20%) within 16 km, and cropland (49%) and water (33%) within 80 km.

3 km
65 m
16 km
125 m
80 km
251 m
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: London 24 km · Tillsonburg 38 km · Strathroy 41 km · Woodstock 53 km · Norfolk County 65 km · Stratford 69 km · Brant 79 km · Brantford 84 km

Canada travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 83% of US
price level, 2025
GDP per capita
$55,698
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
97%
of population, 2024
Homicide rate
2
per 100k, 2023
Road deaths
5.3
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 53%none 35%Muslim 5%Hindu 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for St. Thomas (42.7736°, -81.1804°, elevation 232 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).